The present invention relates to a simplified method for making an impermeable joining on three-layer or bi-layer fabric materials, either with or without a complex construction on a joining side thereof and being preliminarily joined by a stitching or ultrasound joining arrangement.
Composite textile articles, made by coating or laminating textile materials with barrier membrane layers, to provide liquid impermeable fabric materials are already known.
The above articles or products are called “laminated” articles and are conventionally used for making protective garments or other liquid proof or impermeable products and articles.
The laminated fabrics are constituted by two or more laminated fabric layers, at least one of which is a barrier-membrane.
A most common three-layer laminated arrangement comprises an outer fabric material, a barrier-membrane and a complex textile construction, such as a fleece-pile construction, constituting the inner layer.
The outer fabric material is a textile layer of different types which may either comprise or not a complex textile material.
The barrier-membrane consists of a synthetic material film which is transpirable for liquids in a direction, from inside to outside, while being impermeable to liquids in the opposite direction.
By the term “complex textile construction” (that is the inner layer) a variously processed (shaped, engraved, raised fabric material) textile article or a fibrous or filamentary construction is meant which may comprise either woven or non-woven textile, brushed, raised, carded and the like materials.
Laminated fabric materials are at present used for making garments, coatings or linings and other liquid transpiring and impermeable articles or products.
The above products are also conventionally called “soft shell” articles, since they may comprise flexible and soft junctions, a long duration complex textile material on the outside thereof and a soft textile material on the inside thereof to provide good wearing and comfort properties.
The above mentioned prior articles are made by very complex making methods providing to remove large textile material amounts and use additional sealing strips.
Laminated textile products or articles are also known which are impermeable to liquids on their outside but transpiring from their inside to their outside.
In the garment industry, no reliable, efficient and inexpensive method is at present available for joining two or more laminated textile material panels or pieces to provide a complex textile construction including a joined or seamed or stitched portion having permanent impermeableness characteristics, together with a satisfactory flexibility and softness.
In fact, in making impermeable junctions on two, three or multiple layer laminated fabric materials having a very complex textile construction inner layer, a lot of difficulties have been encountered, which are caused by different reasons.
At first, liquids may enter the textile materials through the so-called “wick” or capillarity effect.
Moreover, it is not possible to prevent liquids from entering the textile materials by applying on the outside of said materials adhesive sealing substances, such as fluid sealing substances, since it would be necessary to perform a full impregnating only of the sealing region, which operation, besides being difficult, would cause an unacceptable stiffening of the fabric joining part being processed.
In fact, the individual threads or yarns forming the textile layer comprise a plurality of filaments defining gaps therebetween which cannot be easily sealed by conventional sealing methods, thereby liquids are easily absorbed because of the above mentioned wick or capillarity effect.
Moreover, prior sealing methods disadvantageously comprise three different operating steps, that is a preparing of the textile or fabric material, a joining of the prepared fabric materials and a sealing of the joining region.
In said fabric material preparing step, and because of the above disclosed passage of liquids through the textile fibers, it is necessary to remove the inner layer of the complex textile material at the sealing area to arrive at the protective barrier layer surface which constitutes the textile material impermeable part.
This preparing step is per se a shaving or scarifying step which must be carried out on different machines and by different methods such as shaving, scarifying and sandblasting apparatus and processes.
In the above joining step, after preparing the fabric panels on pieces as above disclosed, said panels or pieces are joined by different joining methods, such as seaming, ultrasound and high frequency methods, while leaving, at the joining sides, an impermeable protective barrier portion exposed to the view.
After joining the fabric panels, it is moreover necessary to seal the joining regions, which operation is performed by sealing taping machines which hot apply an adhesive impermeable tape or strip on the protective barrier portions left free on the sides of the joining regions.
Thus, the joining regions are finally sealed and will have the desired impermeable properties.
This sealing is achieved by causing the adhesive tape or strip to adhere to a preliminarily uncovered impermeable portion of the protective barrier.
Thus, the above mentioned prior methods comprise three main operating steps, that is a preparing, a joining and a sealing steps, each of which must be carried out either in a single or in multiple operations.
The shaving operation, in particular, is a very delicate and difficult one since, during this step, the barrier membrane may be easily damaged or textile fiber portions may be left unprocessed.
In some cases, the fabric material characteristics, such as a poor adhesion between the outer fabric material and the underlying barrier membrane, or a heavy use of the garment article, requires to preliminarily mechanically connect or join the fabric panels, which operation is performed either by seaming or ultrasounds, since merely welded or sealed joins cannot provide sufficient sealing properties, the joining region being then, as stated, made impermeable by taping.
Thus, in actual practice, prior impermeable joining methods require four operating steps: a mechanical scarifying of the fabric pile on the inner side of the first panel; a further mechanical scarifying of the second fabric panel; a joining of the two scarified fabric panels by sealing or ultrasound joining operations, and an application of an impermeable tape or strip on the joining line.
As mentioned, said two mechanical scarifying operations are very difficult to perform and require a long operating time.